A motor vehicle door typically includes an outer sheet metal panel, an inner sheet metal panel, and a plurality of hardware components mounted within an inner cavity formed between the outer and inner sheet metal panels. Common hardware components mounted to a door body include inner and outer door handle assemblies, window regulators, latch assemblies and speaker assemblies, along with their ancillary connecting and electrical components. The complete assembly of the door involves multiple manufacturing steps and numerous parts. Conventionally, an original equipment manufacturer (OEM) will install each individual hardware component to the structural door body along an assembly line.
In general, vehicle occupants are less protected against side-impact collisions than front or rear-end collisions due to the relative thinness of the motor vehicle door. The door body itself can be forced into the passenger compartment, since the door body typically absorbs only a limited portion of the collision energy. Additionally, rigid hardware components that are mounted between the outer and inner sheet metal panels can also be forced into the passenger compartment. To improve safety in side-impact collisions, the vehicle door is typically reinforced by strengthening the sheet metal panels, or by mounting reinforcing structures such as crash beams to the door body. Additionally, one or more energy absorbing foam blocks are typically mounted between the inner and outer sheet metal panels to reduce the severity of a side-impact collision.
The conventional installation of the hardware and safety components has, however, several drawbacks. First, a high assembly cycle is required to assemble the door in this fashion since installation of each hardware and safety component is a separate task requiring human effort. Hardware components must be mounted to the door body and then interconnected. Second, operability of the hardware components cannot be determined until the respective components are installed onto the door. Thus, time and labor may be wasted installing inoperable or ill-fitted components. Finally, additional time is required to inventory each hardware component as it arrives at the OEM to ensure that all of the hardware components are available for assembly.
Pre-assembled door modules have been proposed to overcome some of the deficiencies of conventional door assembly methods. A door module typically involves using a carrier plate to partially assembly and orientate hardware components thereto prior to installation to the structural door body. One disadvantage associated with such door modules is that once the door module is installed to the door, the carrier body typically serves little or no purpose since all of the hardware components are eventually securely fastened to the structural door body and the door module itself does little or nothing to strengthen the door body. Another disadvantage associated with such door modules is that the door modules themselves are very labour intensive and require a large number of parts and steps to assemble before they can be delivered to the OEM.
It is therefore desired to provide a door module that adds structural support to a motor vehicle door body, provides greater protection to passengers, and is easy to assemble at an OEM plant.